[
  { "account_id": "a", "currency": "EUR", "net_revenue": 8, "ai_cost": 1, "contribution": 7 },
  { "account_id": "a", "currency": "USD", "net_revenue": 15, "ai_cost": 5, "contribution": 10 },
  { "account_id": "b", "currency": "USD", "net_revenue": 10, "ai_cost": null, "contribution": null },
  { "account_id": "c", "currency": "USD", "net_revenue": null, "ai_cost": 4, "contribution": null },
  { "account_id": "d", "currency": "USD", "net_revenue": null, "ai_cost": 2, "contribution": null },
  { "account_id": "e", "currency": "USD", "net_revenue": 7, "ai_cost": null, "contribution": null }
]